This invention relates generally to semiconductor devices and methods of making same, and more particularly the invention relates to photoresist masking techniques as used in semiconductor device fabrication.
The fabrication of semiconductor integrated circuits and discrete devices requires the selective introduction of dopants into a monocrystalline semiconductor body and the formation of electrical contacts to selected surface regions of the semiconductor body.
The selective introduction of dopants typically entails ion implantation or atomic diffusion of the dopant through openings in an oxide layer on the surface of the semiconductor body. The openings in the oxide layer are formed by photoresist masking of the oxide layer and chemical (wet or plasma) etching of areas of the oxide layer exposed through the photoresist layer.
Device yield can be greatly affected by a number of factors including the cleanliness of the surface of the semiconductor body, the quality of the photoresist coating of the semiconductor surface, proper exposure of the desired pattern in the photoresist, removal of the unwanted photoresist after exposure by a suitable developer, etching of the exposed semiconductor layer, and finally the removal of the resist material after openings in the oxide layer are formed.